Based on its kinetic, no-nonsense advertising campaign and tick-tock bank heist plot, who would guess that “Inside Man” is (to use the technical term) a Spike Lee joint? Spike Lee, that polarizing explorer of race and social tensions in modern-day America, directing a bank heist movie? The fit seems incongruous at best, the usual Spike-d cocktail of provocation and profundity all but absent. Lee’s foray into the “genre picture,” however, is but the latest in a series of traditionally “studio” films helmed by innovative and independent-minded directors.

Lee provides an intriguing case study. Set (where else?) in New York City, “Inside Man” begins with signature shots of a bustling Big Apple morning: taxis inching their way through Midtown traffic, street-venders hawking their wares, and, as the “Directed by Spike Lee” title flashes across the screen, a close-up of the intersection of Broadway and Wall Street. At the risk of reading too much into potentially arbitrary opening credits, this image provides a strikingly visual interpretation of the cross-section of motives driving directors best known for small, non-studio projects to big Hollywood. After 2004’s critically lambasted and commercially insignificant “She Hate Me” led some to ring the death knell on his once-white-hot career, one can see the appeal that Russell Gewirtz’s tight, terse “Inside Man” script would have to Lee. In three weeks, the film has out-grossed his most commercially successful film by almost twenty million dollars.

Not that Universal Studios, which released “Inside Man,” relied upon Lee’s name recognition (or lack thereof) to fuel any box office bonfires. Surveying the film’s poster, the viewer must squint to see his name amidst the credits that line the bottom. The film itself seems to support the opinion that Lee did not intend the movie to plaster him on magazine covers. The professionalism with which he structures key suspense sequences is admirable for its lack of bombast (a flaw pervasive throughout Lee’s career) as well as its technical prowess. At its very best, “Inside Man” radiates with the cool delight its director seems to take in sinking his teeth into an old-fashioned heist flick.

This is coupled by the encouraging signs that Lee has not doused his volatile cinematic spirit in the service of ticket sales. Gewirtz’s script allows Lee to explore, at least tangentially, his fascination with intersecting ethnic conflicts in post-9/11 New York. Because these thoughts reside in the periphery of the script, said intersecting ethnic conflicts (a Sikh refusing to be questioned because he was mistaken for an “Arab,” etc.) do not resonate deeply. By having race enter but not dominate the film, though, it allows the tightly-wound suspense to take center-stage, reminding the audience that Lee’s relevance as a director extends beyond his oft-cited role as cinema’s resident aging firebrand.

Directors who have taken a similar route as Lee has with “Inside Man” seem connected by this idea of imbuing their distinctive styles and obsessions into more traditional genres. One has to look no further than Hitchcock to examine a filmmaker whose work within that most shop-worn of genres, suspense, often resulted in deeply personal explorations of sexuality and desire.

In the modern day, fans and novices embraced Christopher Nolan’s franchise-rebooting “Batman Begins.” A linear popcorn picture with an all-star cast and multimillion dollar budget seems miles away from the time-warping, neo-noir world of Nolan’s breakout 2001 masterwork, “Memento.” Upon closer observation, though, both explore the psyches of scarred, brooding anti-heroes within the thriller setting (one just happens to have a penchant for form-fitting rubber body suits). Sam Raimi, whose career began with such cult horror classic as “The Evil Dead” and moved onto the critically acclaimed “A Simple Plan,” brought Spider-Man, the much beloved comic book superhero, out of Hollywood development hell and onto the silver screen, launching the careers of Tobey Maguire and Kirsten Dunst in the process. The “X-Men” franchise received a similar shot in the arm from Bryan Singer, Oscar winner for the beloved neo-noir “The Usual Suspects.”

Unlike Lee, the earlier works of all three of these directors more directly influence the genres they continue to direct. “Memento” or “The Usual Suspects” revitalized the noir, giving it modern-day punch and power. “The Evil Dead,” meanwhile, both subverts and pays homage to the monster movies of yesteryear. In other words, Nolan, Singer, and Raimi are not making a radical leap so much as helming the kinds of movies their earlier works were influenced by either implicitly or explicitly.

Launching into the world of Hollywood, particularly if your films succeed as these men’s films have, naturally comes with lucrative multi-film contracts and insider perks. And while one cannot and should not assume anything regarding what leads directors to sign on with the big studios, it would be equally ignorant to pretend the siren song of mainstream acceptance does not go hand-in-hand with the choice to take on massive Tinseltown projects.

And it doesn’t seem as if the trend is stopping anytime soon. Raimi is locked in for “Spider-Man 3,” Singer’s “Superman Returns” explodes into multiplexes June 30th, and Nolan is in negotiations to helm the currently untitled “Batman” sequel. In addition, hipster-auteur Wes Anderson is currently filming the animated adaptation of the Roald Dahl children’s book, “The Fantastic Mr. Fox,” and Spike Jonze, the directorial mind behind such brainy, thoroughly adult concoctions as “Being John Malkovich” and “Adaptation,” will next be represented by his adaptation of the classic picture book, “Where the Wild Things Are.” Both are scheduled to be in theaters by the end of 2007.

So, is this trend ultimately good for film lovers? Do we want our best and brightest new directors feeding from the hands of bottom-line-obsessed studio honchos? The answer rests on a case-by-case basis. If artists like Nolan and Singer can balance their distinctive voices with the unique demands and rewards of mainstream filmmaking, more power to them. Still, let’s hope they don’t completely lose their wild sides.

Certainly Mr. Lee shows no signs of this. He’s currently in pre-production on a documentary entitled “When the Levees Broke,” as sure an indication as any that it’s going to take more than a mainstream hit or two to silence the questions that lie at the heart of all of Lee’s work.